Caffeine Stacking Calculator
Most caffeine calculators only count one drink at a time, but most people stack coffee, an energy drink, and pre-workout in the same day. Add every source you've had to see your real total against safe-limit guidance. Nothing uploaded.
Caffeine Sources Today
Total Caffeine Intake
General guidance only, not personal medical advice. Individual caffeine sensitivity varies.
Learn more: Daily caffeine intake and stacking
How caffeine stacking works and why it matters
Most people don't realize that they're consuming caffeine from multiple sources in a single day. A morning coffee (95mg) plus an energy drink (160mg) plus pre-workout (200mg) totals 455mg - exceeding the FDA's 400mg safe limit before noon. The calculator sums every source you add throughout the day and compares your total against the recommended safe limit. This matters because the effects are cumulative: you'll experience stronger jitters, elevated heart rate, anxiety, and potential sleep disruption when multiple sources are combined. Even a small third drink can push you over the safe threshold.
Pregnancy, caffeine metabolism, and individual sensitivity
The 400mg safe limit applies to healthy, non-pregnant adults. During pregnancy, the safe limit drops to 200mg per day due to evidence linking higher caffeine intake to increased miscarriage risk. Breastfeeding mothers should also limit to 200mg daily because caffeine passes freely into breast milk, and infants lack the liver enzymes to metabolize it efficiently. Individual sensitivity varies widely: some people feel effects at 100mg, while others tolerate 600mg. Age, body weight, medications, and genetics all influence how quickly your body processes caffeine, so the calculator's guidance is a general reference, not personalized medical advice.
FAQ
What is safe daily caffeine intake?
The FDA and most health authorities cite 400mg per day as a safe limit for healthy adults. During pregnancy, the safe limit drops to 200mg per day due to risks of miscarriage. Breastfeeding mothers should also limit to 200mg daily because caffeine passes into breast milk and infants cannot metabolize it efficiently. Individual tolerance varies greatly - some people experience jitters at 100mg, while others tolerate 500mg without issues.
Why does my energy drink contain so much caffeine?
Energy drinks typically contain 80-160mg per can because manufacturers target people seeking a significant energy boost. A standard cup of coffee has about 95mg, so energy drinks match or exceed that in a smaller volume. Pre-workout powders push even higher at 150-300mg because they're designed for intense training sessions. When you stack these sources (coffee + energy drink + pre-workout), you can easily exceed 500mg before lunch.
How long does caffeine stay in my body?
Caffeine has a half-life of about 5 hours in adults, meaning 50% is cleared from your system every 5 hours. If you drink 200mg at 8am, 100mg remains at 1pm, and 50mg at 6pm. Pregnant women, people on certain medications, and those with liver conditions metabolize caffeine more slowly. Consuming caffeine after 3pm can disrupt sleep for many people. This calculator doesn't account for time-of-day effects - it just sums your total intake.